mag tape vs memory device

mag tape and memory device both are nouns.

Word	Noun	Adjective	Verb	Adverb
mag tape	Yes	No	No	No
memory device	Yes	No	No	No

As nouns, memory device is a hypernym of mag tape; that is, memory device is a word with a broader meaning than mag tape:

mag tape: memory device consisting of a long thin plastic strip coated with iron oxide; used to record audio or video signals or to store computer information
memory device: a device that preserves information for retrieval

Other hypernyms of mag tape include storage device.

mag tape (noun)	memory device (noun)
memory device consisting of a long thin plastic strip coated with iron oxide; used to record audio or video signals or to store computer information	a device that preserves information for retrieval